1. Background of Invention
Endoscopic ultrasound procedures have been used for more than twenty five years within the field of medicine. These procedures allow clinicians to scan, locate and identify individual layers of a patient's gastrointestinal tract to determine the location of individual mucosal and sub-mucosal layers. Once identified, appropriate therapeutic modes of treatment for malignancies and various abnormalities may be determined by a clinician.
An endoscopic ultrasound procedure may consist of several steps. For example, a clinician may sedate a patient and insert a probe via esophagogastroduodenoscopy into the patient's stomach and duodenum. An endoscope may then be passed through the patient's mouth and advanced to the level of the duodenum. From various positions between the esophagus and duodenum, organs or masses outside the gastrointestinal tract may be imaged to determine abnormalities. If any abnormalities are present, the organs or masses can be biopsied through fine needle aspiration. Organs such as the liver, pancreas and adrenal glands are easily biopsied as are any abnormal lymph nodes. A patient's gastrointestinal wall can also be imaged to determine the presence of any abnormalities. For example, abnormal thickness within a patient's gastrointestinal wall may be suggestive of inflammation or malignancy.
The quality of images produced via endoscopic ultrasounds is directly proportional to the level of frequency used. Although a high frequency ultrasound can produce a higher image quality, high frequency ultrasounds do not penetrate organ walls as well as lower frequency ultrasound. As a result, the examination of the nearby organs is not possible.
Mediastinoscopy is a prevailing method for determining the presence of nodal metastases in the mediastinum. Generally performed as an outpatient surgical procedure, mediastinoscopy is associated with a low rate of serious adverse effects and is considered to be highly accurate. Endobronchial ultrasound guided fine needle aspiration biopsy of mediastinal nodes offers a less invasive alternative for histologic sampling of the mediastinal nodes. Endobronchial ultrasound has been widely adopted by pulmonologists and is poised to replace mediastinoscopy in the future. For thoracic surgeons, endobronchial ultrasound can be easily learned and it may be important to do so if their specialty is to maintain the traditional and important role in the diagnosis and staging of thoracic malignancies.
During endobronchial ultrasound, a clinician can perform needle aspiration on lymph nodes using a bronchoscope inserted through the mouth. For an endobronchial ultrasound procedure, an endoscope fitted with an ultrasound processor and a fine-gauge aspiration needle is guided through a patient's trachea. Once appropriately positioned, the needle portion of the fine needle aspiration device is advanced into the lymph node, the sample aspirated, and device is removed from the bronchoscope.
Endoscopic ultrasounds and endoscopic bronchial ultrasounds through fine needle aspiration are presently standard modes of treatment in the field of gastrointestinal endoscopy and bronchoscopy. These procedures traditionally result in high yields of sensitivity and specificity in the management of indications of diseases such as esophageal cancer, pancreatic cancer, liver mass, non-small cell lung cancer, pancreatic mass, endobronchial mass, and intra-abdominal lymph nodes.
An endoscopic ultrasound through fine needle aspiration requires a fine needle aspiration device that is attached to the luer port or working channel of a typical echo-endoscope. Traditional devices utilize a series of push and pull handles to control the axial movement of the catheter shaft of the device and the depth of needle penetration. These device, however, suffer from several drawbacks.
For example, the means of attaching a device to an echo-endoscope is cumbersome. Devices presently utilize male fitting adapters that must be screwed onto a female luer port of an endoscope. In addition, these devices provide sub-optimal ergonomics of use. More specifically, a clinician must actuate a number of handles independently and lock respective handles in position via cap screw arrangement to secure the device. The cumulative actions required by a clinician result in significantly drawn out procedures. Further, needles commonly kink or deform during removal from a device causing numerous delays and failures. Moreover, multiple passes per procedure are required, which prolong the procedure and result in a clinician needing to reconfirm the location of a needle relative to a desired aspiration site with each new pass.
Another drawback involving a typical echoendoscope concerns the lack of needle safe preventative design features which protect the clinician from inadvertent needle penetration and the transfer of blood-borne pathogens from a patient to attending medical staff. In the case of currently available fine needle aspiration medical devices for both endoscopic ultrasound and endo-bronchial ultrasound, once a sample has been aspirated from the desired anatomical location, the fine needle aspiration catheter is removed from the echoendoscope and handed to the clinician for sample extraction and preparation. The clinician is instructed to “re-sheath” the needle (i.e. retract the needle into the catheter sheath) prior to detachment from the echo-endoscope. However, in many instances, this does not occur. As such, the needle sharp of the device is exposed during removal and transfer of the fine needle aspiration device among medical staff in the endoscopic ultrasound and endo-bronchial ultrasound suite with increased risk of “needle sticking” and blood borne pathogen contamination and exposure to same.
Additionally, needles are commonly used in medical procedures, with biopsy being a primary field of use for such devices. In the case of Endoscopic Ultrasound (EUS) and Endo-bronchial Ultrasound (EBUS), the efficiency of the ultrasonic procedure relies on the ability to direct the needle component to the desired site of sample acquisition. Smooth cylindrical surfaces of needles are unfortunately very difficult to image using ultrasonography due to the specular (mirror-like) surface finish of the needle in the untreated state. To address this problem, various techniques have been developed to enhance the echogenicty or ultrasonic visibility of needles. Various techniques (sandblasting, surface etching and coating of surfaces) have been used to “roughen” the surface of a needle component with limited success. This surface roughening results in a scattering of rays from the ultrasound. However, some of the drawbacks of the aforementioned techniques concern the angle of incidence (sound waves from the ultrasonic transducer) and the angle of reflection (sound waves reflected back to the transducer array). It is important that the method and design of surface finish and surface deformation imparted to the needle of the biopsy device maximize the percentage of waves reflective which can be picked up by the ultrasonic array.
Therefore, a need exists for improved devices for use in endoscopic ultrasound procedures.